1. Field of the Invention
The present invention generally relates a data processing apparatus. More particularly, the invention relates to a data processing apparatus adapted to operate in a power saving mode, and a method for processing data in the power saving mode.
2. Description of the Related Art
Among the known data processing apparatuses is one in which supply of power to a main controlling section including a central processing unit (CPU) is interrupted for minimizing power consumption. When a data processing apparatus is in a power saving mode, if the apparatus is to enter a data processing mode, the power supply must be supplied to the main CPU for the main CPU to resume execution of a control program. It is common that the apparatus jumps back to, for example, the top of a BOOT program held in a RAM so that the main CPU can execute the control program. Japanese Patent Application Laid-Open No. H11-24914 discloses one such apparatus. However, such a procedure fails to identify whether an operator depresses a power saving key of the data processing apparatus or the operator places a document on a document reading device, and gives no consideration to how the control program should be executed depending on these external events. This requires some time before a user's desired function becomes ready to operate, causing inconvenience to the user.